Seals for bearing assemblies are necessary in machines such as pumps, turbines, agitators and the like to seal bearings contained in housing. The bearings in the housing support shafts which normally protrude from both ends of the bearing housing.
The bearings require lubrication and an absence of contaminants to properly operate. At the point where the shaft protrudes from the bearing housing seals are necessary. Due to the rotation of the shaft and the stationary housing it is also necessary to use seals which minimize frictional losses and heat generation.
In high contaminant environments effective sealing is especially important. Labyrinth seals are well-known in these types of applications wherein different members of the seal assembly interconnect to form a tortuous labyrinth making it especially difficult for contaminants to penetrate the seal and affect the bearings.
One type of seal is sometimes called a "Taconite Seal" which is a premium seal used for contaminated environments, ie. mining or heavy equipment operations where excessive dust and dirt particles are present. Taconite seals typically have a labyrinth and a number of additional sealing elements. Often these sealing elements include lip seals or v-ring seals which contact the surface of the shaft during rotation. In some cases these seals actually rotate with the shaft inducing friction, heat and ultimately seal failure. Most types of labyrinth seals include means to purge grease through the seal by applying grease into the labyrinth under pressure.